Yes, a scalp massager can be used on dry hair. Dry hair can benefit from the use of a scalp massager as it helps to stimulate blood circulation, exfoliate the scalp, and distribute natural oils throughout the hair. Using a scalp massager on dry hair can also help to relieve tension and promote relaxation. However, it is important to use gentle pressure and avoid any harsh or aggressive movements to prevent any potential damage to the hair or scalp. Additionally, it is always recommended to follow the manufacturer's instructions for the specific scalp massager you are using.